In view of climatic changes, it is a global objective to reduce the emission of pollutants into the atmosphere. This applies particularly to the emission of carbon dioxide (CO2) which accumulates in the atmosphere, hinders radiation of heat from the earth and thus leads, as greenhouse effect, to an increase in the surface temperature of the earth.
Particularly in the case of fossil fuel-fired power stations for generating electric energy or heat, a carbon dioxide-containing gas or flue gas is formed by combustion of a fossil fuel. To avoid or reduce carbon dioxide emissions into the atmosphere, the carbon dioxide has to be separated from the flue gas. Accordingly, suitable measures for separating the carbon dioxide formed after combustion from the flue gas (post-combustion capture) have been discussed, particularly in the case of existing fossil fuel-fired power stations.
For industrial implementation, the carbon dioxide present in the flue gas is for this purpose scrubbed out of the respective flue gas stream in a removal apparatus by means of an absorption-desorption process using a suitable scrubbing medium or absorption medium. In such a process, cooling of the apparatus components used in the removal apparatus or of the corresponding fluid streams is necessary. Thus, for example, it is necessary to cool the gas stream before entry into the absorber of the removal apparatus, to cool the scrubbing medium used for absorption of carbon dioxide and likewise to cool the carbon dioxide-rich gas outlet stream at the top of the desorber.
Liquid-cooled cooling units and in particular water-cooled cooling units are frequently used for this purpose. However, water cooling is problematical at, in particular, sites where no water or only small amounts of water is/are available. The use of water-cooled cooling units is not economical here since bringing water to the desired sites is associated with great complication and, resulting therefrom, with correspondingly high costs.